1. Field of the Invention
This invention relates generally to optical display devices that produce spatial objects, and more particularly to a video wall that produces complex layers of projected images that interact to create the appearance of a three-dimensional holographic display.
2. Description of Related Art
Optical display devices that image an object seemingly floating in space have been known for many years. The two most common methods of producing floating objects has been by either reflecting an object from one or more curved mirrors (i.e., parabolic) or viewing an object properly positioned behind one or more lenses. These methodologies are termed reflective or transmissive spatial object devices, respectively.
One means of providing a background image spatial object display is taught by Monroe (U.S. Pat. No. 5,257,130). In this disclosure, a scrim is used to permit a spatial object (produced by either reflective or transmissive means) to appear in front of the scrim (the optical rays forming the object having passed through the open mesh weave of the scrim). The scrim simultaneously serves as a front projection screen surface on which the background image can be projected.
Another means of providing a background image spatial object display is taught by Warren et al. (U.S. Pat No. 5,311,357). Warren discloses the use of two concave mirrors to produce a spatial object with one of the concave mirrors being partially transparent. Behind this partially transparent mirror is an image display which can be readily seen by an observer through the partially transparent concave mirror. Although this device does provide a spatial object floating before a background image, it suffers from several disadvantages. First, the partially transparent concave mirror is an excessively expensive custom optical component. Second, the curve of the partially transparent concave mirror visibly distorts the background image. Third, the background image, on a large screen display, is positioned far back into the device, creating the awkward necessity of peering into a black box. Finally, this device does not provide a means to enhance the 3-D appearance of the background image so that the background image always appears flat.
Still another background image spatial object display is taught by Noble (U.S. Pat. No. 4,671,625). This transmissive spatial object display utilizes a combination of convex lenses with improved viewing of the spatial object provided by a visible reference around the area in which he spatial object appears to serve as a visual cue for the observer. This visible reference is taught primarily as the edge of a box (i.e., shroud) that extends out from the closest convex lens to the observer. A background image is provided by reflecting the spatial object off a partially transparent mirror with the image behind in an optical arrangement similar to Warren, except that this partially transparent mirror is flat and is not used to create the spatial object. In Noble, the transmissive spatial object is created by a transmissive spatial object image produced by a transmissive object display (i.e., CRT). A first convex lens and a second convex lens manipulate the light rays to produce the transmissive spatial object. The transmissive spatial object is viewed from as the reflection of a partially transparent mirror. This mirror folds the beam of the transmissive spatial object and allows a background image (i.e., a poster or full motion display) to appear behind the partially transparent plane that enables the observer to comprehend the spatial position of the transmissive spatial object. As a result, the transmissive spatial object appears to float within the housing and does not protrude beyond the visible reference of the housing opening edges, where it would create a much greater visual impact. This visible reference operates in conjunction with an optional second visible reference located near the convex lens to assist the viewer in accurately aligning the object in space. Unfortunately, peering deep into this box to view the image is somewhat unnatural and may be an irritant to observers accustomed to interacting directly with a television screen or a computer monitor. Also, by recessing the image deep within a box, only a single observer at a time can peer into the box to view the image. As a result, this device is unable to communicate simultaneously with multiple observers. Noble also does not teach how to provide a background image behind these two spatial objects, nor does he offer a method of reducing the bulk of the display necessitated by two full sets of optics. Nor does he teach a method for reducing reflections on the first convex lens, other that the shroud. Also, the configuration he teaches requires both spatial objects to be contained within the box behind the edges of the box forming the transparent plane of the visible reference means.
Machtig et al. U.S. Pat. No. 5,782,547 describes an improved transmissive spatial object display that provides a background image that appears to observers to have 3-D depth and includes the added advantages of permitting several viewers to observe the display simultaneously so that the background image appears on an accessible screen like that of televisions and computer monitors. The background image display is observed directly through a first Fresnel lens of a two Fresnel lens transmissive spatial object display which lens magnifies the background image display and also provides the front screen of the device. A first partially transparent mirror at 45 degrees separates the two Fresnel lenses permitting the background image display to be viewed solely through the first Fresnel lens. The first Fresnel lens serves the dual function of creating a first spatial object (in combination with the second Fresnel lens) and magnifying the background image. The magnified background image appears through the first Fresnel lens creating a pseudo 3-D appearance even though the background image is generated by a 2-dimensional display such as a CRT. Video production techniques can enhance this illusion of dimensionality through isolation of objects and graphics on a black field and use of dimensionalizing techniques such as reflections and shadings. Alternate embodiments provide projection of multiple spatial objects. Additional embodiments are configured without the second Fresnel lens so that the first Fresnel lens serves to magnify the background display's image and by itself creates the first spatial object.
The prior art teaches a transmissive spatial object display that provides an image that appears to observers to project into space. However, the prior art does not teach an improved transmissive spatial object display that covers an entire wall and provides a complex and multilayered image that appears to observers to have 3-D depth. The present invention fulfills these needs and provides further related advantages as described in the following summary.